Horn



1951 w. A. GARRATT 2,565,363

HORN

Filed Feb. 15, 1946 INVENTOR.

W W WKZ1M Patented Aug. 21, 1951 UNITED STATES PATENT OFFICE HORN Walter A. Garratt, Covington, Ky, assignor to Philip G. Vondersmith Application February 15, 1946, Serial No. 647,726

10 Claims. 1

This invention relates to horns and is particularly directed to horns of the type adapted for use on automobiles, boats, bicycles, or vehicles of any sort for giving warning of the approach of the vehicle. The invention is primarily concerned with a sound creating device of that character in which the sound is created by the rapid opening and closing of a valve, the vibratory motion induced'by means of air delivered under pressure.

It hasbeen the primary object of the present inventor to provide a horn of this character which will produce a large volume of sound through the application of relatively little air pressure and very little volume of air. This inventor has discovered a novel structural arrangement for efficiently utilizing the air pressure consisting of an improved valve mounting and actuating means which enables thejproduction of sound in such volume as to produce ample warning by the application' of an air compressing force so small as to be produced by a light fingertip pressure.

Ithas been a further object of this inventor to provi'de'a horn of this character which will produce a melodious tone of sufiicient volume for warning purposes.

More specifically described, it hasbeen the purpose to providea valve moved relative to its seat by means of the application of the air pressure to anunusually large'jarea,all of which is fully effective'for inducing valve action and further to provide a valve actuating'structure which includes noloose parts or springs. Thus, the valve is exceedingly sensitive to the very, lowest air pressure andthesound thereby produced is without metallic" rattle or harsh vibration;

Itjhas been a further object ofrthe present inventor to provide a horn of thetypeemploying a valve in which the valve is rigidly fixed to its actuating means so as to firmly and positively engage its seat as it moves relative thereto. In other words, the valve cannot wobble or tip, the means for mounting it being suificiently flexible to permit movement of the valve directly away from the seat, that is, in a direction'at right angles tofthe'seat; but, in noevent can the valve move laterally.

A still further object has been to provide a .drum like receptacle, one wall of which has the valve rigidly attached thereto. The drum-like element has" flexible walls, the flexing of its valve carrying wall actuating the valve relative to the seat and the effect of the delivery of the air under pressure into the drum-like element being to produce a'resjonant and musicaltone. In other wordathe' vibration'as carried through the valve into the Valve carrying wall of the drum-like support creates sound which is more resonant as above noted.

Further, it is a purpose to provide a valve which has a resilient or yielding engagement with its seat and therefore, due to the tendency to maintain its seated position up until the time that the metal returns to its normal unflexed condition following yielding contact with the seat, the actual opening of the valve is more instantaneous. In other words, the valve unseating movement is under way for a period of time before actual unseating takes place and, thus, the valve leaves the seat very suddenly. This increases the volume of sound since the rush of air past the valve is faster and the vibration of the air column more violent.

Further objects and certain advantages of the invention will be more fully apparent from a description of the drawings, in which:

Figure 1 is a general side view of a horn in whch the present improvements have been incorporated.

Figure 2 is an end view thereof.

Figure 3 is an enlarged sectional view taken diametrically through the improved sound producing unit of the horn.

Referring to the drawings in general, the means for producing the air pressure or the column of air is shown at 5, the sound directing and amplifying member at 6, and the sound producing unit at I. The sound producing unit includes a compressed air delivery nipple 8 to which is connected the hose 9 through Which is conducted the compressed air.

Any type of air compression means may be employed and it is pointed out that the means for producing the compressed air need not be of any great size. In the drawings, a small bulb indicated at [0 has been shown. A small plunger, depressible by finger pressure, may be utilized. The main point is that the air producing means may be one requiring very litle force to operate it, since, as stated, a sufiicient amount of force may be produced by a light fingertip pressure.

The nipple 8 is secured by welding or the like to the end plate member ll of the casing l5 of the sound producing unit. The sound conducting nipple I2 is secured centrally axially of the unit '5 to the end plate by means of welding. The delivery nipple is, as shown, positioned off-center. The end plate includes a marginal flange 13 which is turned in a direction opposit to the direction in which the nipples are extended. That portion of the end plate marginally surrounding the nipple !2 is formed to provide a raised portion l4 constituting a valve seat which will be disposed on the inside of the unit. Thus, a circular valve seat is provided which is rounded so as to provide a good contact.

The cover or main casing element It of the sound producing unit is a cup-shaped member, the open end edge of which is disposed within the flange I3 for holding the valve operating means IS in position. The outer wall I? of the casing I5 is convex, or curved and a tension clip It holds the casing in position on the plate I l. Centrally of this casing, there is provided a teat l9, cooperating with an indentation 26 on the clip which centers it as shown in Figure 2; that is to say, maintains it in a diametrically disposed position. The tension clip includes, in addition to its diametric portion 25, arms 22 which have hooked portions 23 engaged around the back of the plate I I.

A rubber gasket 24 is interposed between the attaching flange 25 of the valve actuating means and the end plate ll so as to provide a seal for the purposes hereinafter set forth.

The valve actuating means consists, in addition to the attaching flange, a relatively thin drum-like element 25. This drum-like element has one end wall provided with an opening 21, the flange 28 of which is seated and attached within a central opening in the flange plate 1 The walls of this drum-like element are provided with circular depressions forming undulations in diametric section, aiding in the flexing of the walls so that the drum-like member be comes in effect a bellows, the walls of which 1.

will flex and breathe under the influence or the air column, introduced under pressure inio the chamber formed by the drum-like element.

The valve 29 which is formed of a thin metal disc is of a diameter fitting over the seat I l but less than the diameter of the opening 2? so that adequate clearance is provided between the flange 28 and the valve. The flange plate 25 is dished so as to space the drum-like member under way from the plate ll whereby there is no interference in the motion of the valve carry-- ing means. The valve is secured or mounted on the drum-like member by means of a centrai stem or stud 30, screw-threaded through a stiffening washer 3| welded to the outer surface of the closed Wall of the drum, a nut 32 looking the stud in position. The inner end of the stud includes a shoulder 33 afforded by a counter-turned portion. The valve disc is centrally apertured to fit on the counterturned portion along with front and back stiffening washers 34-34. The counterturned portion is peened over to fix the valve and washers permanently and rigidly in position.

Thus, the arrangement of parts provides a chamber 35 which receives the compressed air from the nipple 8, the chamber being sealed off b the gasket 24 and the onl point of discharge therefrom being the nipple l2 past the valve 29. .When the compressed air is supplied to the chamber 35 through the tube 8, the end walls of the drum-like member are forced outwardly, particularly the outer closed wall, thus opening the valve 29, that is, moving it oil its seat M. For reasons explained hereinafter, the valve closes immediately after being forced open and this cycle is repeated rapidly and regularly.

'The operation of this cycle requires the applica- J tion of two forces which are opposite in direcconstituting a Weighting means tion and which are alternatively effective on the valve.

The forces effective in this device for producing the sound are considered to be the followmg:

That force necessary to open the valve is produced by the compressed air in ihe chamber 35 which distends the flexible diaphragm walls of the drum-1ike member. This inflation of the drum-like member pulls the valve oil its seat. The flexed drum ends tend to restore to their former position by reason of their elastic properties.

Added to the force which closes the valve is a consequence of the well-known Bernoulli prin-- ciple explaining certain phenomena occurring in moving liquids and gases; 1. e., in regions where the velocity of flow is increased, the hydro-static pressure of the fluid is less than in the surrounding fluid. Therefore, as applied to this horn, as soon as compressed air opens the valve in the chamber 35, a high velocity jet of air will move through the valve controlled space into the nipple l2. Since the velocity is high, the pressure in the region of this jet will be lowered considerably thus creating a suction on the valve. This fact, plus the natural tendency of the flexed drum Wall to return to normal position, will close the valve. The Bernoulli force tending to close the valve is greater than the influence of the incoming air tending to open same. As soon as the valve closes, the jet of air is eliminated and the Bernoulli force is no longer in existence. This allows the air pressure to build up and open the valve, the cycle being repeated at great speed as long as compressed air is supplied to the chamber 35.

By providing the drum-like element with a suitable weight 3i and utilizing a highly flexible valve, auxiliary forces have been applied which tend to keep the opening and closing of the valve regular and timed, thus producing a pleasant tone.

As the air rushes past the valve and the pressure drops suddenly, the valve seats firmly and being flexible will bend against the seat. Thus, as the pressure in the bellows or drum immediately tends to flex the drum wall and pull the valve from the seat, the first phase of this motion will not unseat the valve, but the motion will be under way before unseating occurs. This causes the valve to leave the seat very suddenly. Therefore, it is obvious that the column of air is vibrated quite violently, the rush of air being substantially explosive.

The area or surface exposed to the compressed air within the chamber 35 is many times greater than the valve surface and, accordingly, it takes very little pressure and very little volume of air to cause the sound producing action of the valve.

. Reference to Figure 3 of the drawings will make clear the considerable expansive force brought to bear in the chamber for unseating the valve.

Another force which is auxiliary to those described is the acoustic loading of the horn which also produces forces on the valve, aiding in producing regularity of operation if the horn is properly tuned to a resonant condition. The pitch of the tone changes as the horn length is varied which shows that these forces change the rate at which the drum wall operates the valve.

The production of sound energy has heretofore been an inefiicient process. This improvement produces a very loud tone with a very small displacement of air, this being due to several factors, among those previously mentioned such as, first, the flexibility andlarge area of the drum wall permits valve unseating, under the action of a relatively small force and through a .low .air pressure and small air volume, second, the drum wall is relatively large so that a low air pressure will exert a large force upon the valve which is of a much smaller area, and third, the sound pro-' ducing unit is insulated mechanically from the horn and the compressed air unit by means of rubber tubing which permits both parts of the sound producing unit to float, to wit: the weighted valve actuating drum wall [6 will vibrate in the opposite direction to that of; the encasing unit which in itself increases theefficiency of the production of sound energy. The resonance of the unit and the coordination of the several forces mentioned, produces a tone which is vibrant and harmonious.-

Having described my invention, I claim:

1. In a horn, a casing;- having an end plate, said end plate having a central opening therein constituting an air outlet, a first nipple leading from the outlet, a valve control member suspended within the casing in spaced relationship to the end plate, means providing an air-tight seal for the space between the valve control member and end plate, a valve seat surrounding the air outlet, a valve rigidly carried by said valve control member and adapted to cooperate with said valve seat, said valve control member constituted by a flexible drum-like element, the interior of which is open to the space between the member and end plate, a second nipple connected to said end plate at one side of the first nipple and constituting means for delivering compressed air into the casing in the space between the member and end plate, whereby upon the delivery of compressed air into said space valve motion is created axially of the outlet to cause the valve to seat and unseat.

2. In a horn, a casing having an end plate, said end plate having an opening therein constituting an air outlet, a flexible drum-like element suspending within the casing in spaced relationship to the end plate, means providing an air-tight seal for the space between the valve control element and end wall, means for delivering compressed air to the casing in the space between th element and end wall, a valve seat surrounding the outlet, and a valve rigidly carried by said element and adapted to cooperate with said seat, the interior of said element being open to the space between the element and end wall whereby said flexible drum-like element expands and contracts as compressed air is supplied to said space causing said valve to seat and unseat.

3. In a sound producing device, a casing, flexible elements forming an elastic chamber within said casing for receiving compressed air, said casing including an inlet opening and an outlet opening in communication'with the interior of said chamber, a valve seat surrounding the outlet, a flexible valve cooperating with said valve seat and atached to one of the flexible elements of the chamber, and means for supplying compressed air to the chamber whereby a vibratory action is set up thus rapidly opening and closing the valve and creating sound.

4. In a sound producing device, flexible wall elements forming a drum-like chamber adapted to receive compressed air, said chamber having an inlet and outlet, said outlet disposed on the axis of the drum-like chamber, a valve seat surrounding the outlet, a valve adapted to seat on said 6 valve seat and attached on an axial line to one of the flexible wall elements of the chamber, and means for supplying compressed air to the chamber whereby a vibratory action is set up rapidly opening and closing the valve andcreating sound 5. In a sound producing device, a casing, a drum-like element having at least one flexible wall disposed within said casing, said element constituting a chamber for receiving compressed air, said casing including an inlet opening and an outlet opening in communication with'said chamber, a valve seat surrounding the outlet opening, a valve adapted to seat on said valve seat and'attached to a flexible wall of-the chamber, the flexible wall of said'chamber having an undulated surface permitting the wall to flex readily, and'means for supplying compressed air to the chamber, whereby a vibratory action is set up for rapidly opening and closing the valve and creating sound.

6. In a sound producing device the combination of a casing having an end plate, said end plate having an entry opening and an outlet opening for air, a drum-like element mounted within said casing and comprising a pair of spaced, facially-cpposed flexible plates and a wall connecting said flexible plates, thereby defining a chamber, one flexible plate of said pair having an aperture in alignment with the outlet opening in said end plate, said aperture being in communication with said inlet opening, a valve cooperating with said outlet opening to control the exit of air therethrough and having a stem extending through the aperture of the first flexible plate of said pair and rigidly fastened to the second flexible plate of said pair, and mean for supplying compressed air through said entry opening, whereby said chamber will expand and contract and said valve will be rapidly seated and unseated in response to compressed air supplied to said chamber.

'7. In a sound producing device the combination of a casing, said casing having an entry opening for the introduction of compressed air and an outlet opening for egress of air, a pressure chamber having a plurality of flexible walls fixed within said casing, said chamber having an opening exposed to said entry and outlet openings in said casing and being sealed in pressuretight communication therewith, a valve adapted to control said outlet opening, said valve having a stem rigidly fastened to one of said flexible walls, means for supplying compressed air through said entry opening whereby as said air is supplied through said opening the flexible walls of said chamber expand until said valve is removed from cooperating engagement with said outlet opening whereupon the chamber contracts expelling air through said outlet opening until said valve is reseated.

8, In a sound producing device of the type ineluding a casing, a pressure chamber mounted within the casing and having at least one pressure-responsive flexible wall, means for introducing compressed air into said chamber, said casing having an outlet opening in communication with the interior of said chamber, the combination of; a rigid valve seat surrounding said outlet opening, a flexible valve adapted to cooperate with said seat to seal said opening, said valve having a stem attached to the flexible wall of said pressure chamber, said valve stem and said pressure chamber being so dimensioned that said valve is disposed in flexed sealing engagement with said valve seat when pressure in said chamber is below a predetermined level whereby when compressed air is supplied to said chamber and said flexible wall expands in response thereto, moving said valve stem away from said exit opening, said valve will remain seated during initial movement of said valve stem and will unseat only when a second higher predetermined pressure in said chamber is exceeded.

9r A sound producing device comprising a casing having a cover plate which is removably held thereto, a chamber fixed within said casing and having a plurality of pressure-responsive flexible walls, means for supplying compressed air to said chamber, a valve seat formed in the cover plate of the casing defining an outlet opening therein, a valve cooperable with said seat to seal said outlet opening, said valve being rigidly attached to one of said flexible walls whereby as said chamber flexes in response to compressed air supplied thereto, said flexible wall produces valve movement relative to its seat.

10. In a sound producing device, a casing having an end plate, said end plate having an opening therein constituting an air inlet and a second opening therein constituting an air outlet, a valve seat surrounding said air outlet, a flexible drum-like element mounted within the casing, said element having an aperture therein concentric with said valve seat, a valve comprising a thin metal disc fixed to a stem, said valve disposed with the disc normally contacting the valve seat for sealing the air outlet and with the stem extending through said aperture and into said element with the end opposite the disc rigidly fastened to the element at a point opposite the aperture, and means sealing the element and end plate in air-tight relationship, whereby compressed air supplied through the air inlet causes the element to flex and thereby produce movement of the valve relative to the seat.

WALTER A. GARRATT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,434,656 Garratt Nov. '7, 1922 1,874,078 Aufiero Aug. 30, 1932 2,068,900 Aufiero Jan. 26, 1937 2,263,342 Lewis Nov. 18, 1941 

